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R. Horowitz  One of the best experts on this subject based on the ideXlab platform.

Passive Velocity Field control (PVFC). Part I. Geometry and robustness
IEEE Transactions on Automatic Control, 2001CoAuthors: P.y. Li, R. HorowitzAbstract:Passive Velocity Field control is a control methodology for fully actuated mechanical systems, in which the motion task is specified behaviorally in terms of a Velocity Field, and the closedloop system is passive with respect to a supply rate given by the environment power input. The control law is derived geometrically and the geometric and robustness properties of the closedloop system are analyzed. It is shown that the closedloop unforced trajectories are geodesics of a closedloop connection which is compatible with an inertia metric, and that the Velocity of the system converges exponentially to a scaled multiple of the desired Velocity Field. The robustness property of the system exhibits some strong directional preference. In particular, disturbances that push in the direction of the desired momentum do not adversely affect the performance. Moreover, robustness property also improves with more energy in the system.

Passive Velocity Field control (PVFC). Part II. Application to contour following
IEEE Transactions on Automatic Control, 2001CoAuthors: P.y. Li, R. HorowitzAbstract:When the contour following task is represented by a Velocity Field on the configuration manifold of the system, the coordination aspect of the problem is made explicit. The PVFC scheme developed in the Part I (ibid. vol.29(9) (2001)) can then be applied to track the defined Velocity Field. However, for some contours, an encoding Velocity held on the configuration manifold does not exist or is difficult to define and, as a consequence, the PVFC cannot be directly applied. For systems whose configuration manifolds are compact Lie groups and the desired contour is represented by a parameterized trajectory, a general methodology is developed, using a suspension technique, to define a Velocity Field on a manifold related to the configuration manifold of the system for which PVFC can be applied. With this strategy, timing along the contour can be naturally varied online by a selfpacing scheme so that the contour tracking performance can be improved. The experimental results for a 2DOF robot following a Lissajous contour illustrates and verifies the convergence and robustness properties of the PVFC methodology.

Passive Velocity Field control of mechanical manipulators
IEEE Transactions on Robotics and Automation, 1999CoAuthors: P.y. Li, R. HorowitzAbstract:Two concepts are advocated for the task specification and control of mechanical manipulators: 1) coding tasks in terms of Velocity Fields; 2) designing controllers so that the manipulator when under feedback control, interacts in an energetically passive manner with its physical environment. Based on these two concepts, a new passive Velocity Field controller is proposed which mimics the behavior of a passive energy storage element, such as a flywheel or a spring. It stores and releases energy while interacting with the manipulator, but does not generate any. The controller has the interesting property that it stabilizes any multiple (positive or negative) of the desired Velocity Field, and exponentially stabilizes the particular multiple of the desired Velocity Field which is determined by the total kinetic energy of the manipulator control system.

Passive Velocity Field control of mechanical manipulators
Proceedings of 1995 IEEE International Conference on Robotics and Automation, 1995CoAuthors: P.y. Li, R. HorowitzAbstract:Two concepts for the task specification and control for mechanical manipulators are advocated: the coding of tasks in terms of Velocity Fields; and controllers that maintain the passivity relationship between the manipulator and its physical environment. A passive Velocity Field tracking controller is proposed. The proposed dynamic controller mimics a flywheel: it stores and releases energy to the manipulator, but does not generate any. The controller has the interesting property that it stabilizes any multiple (positive or negative) of the desired Velocity Field, and exponentially stabilizes the particular multiple which is related to the total kinetic energy of the manipulator+controller.

ICRA  Passive Velocity Field control of mechanical manipulators
IEEE Transactions on Robotics and Automation, 1995CoAuthors: P.y. Li, R. HorowitzAbstract:Two concepts are advocated for the task specification and control of mechanical manipulators: 1) coding tasks in terms of Velocity Fields; 2) designing controllers so that the manipulator when under feedback control, interacts in an energetically passive manner with its physical environment. Based on these two concepts, a new passive Velocity Field controller is proposed which mimics the behavior of a passive energy storage element, such as a flywheel or a spring. It stores and releases energy while interacting with the manipulator, but does not generate any. The controller has the interesting property that it stabilizes any multiple (positive or negative) of the desired Velocity Field, and exponentially stabilizes the particular multiple of the desired Velocity Field which is determined by the total kinetic energy of the manipulator control system.
P.y. Li  One of the best experts on this subject based on the ideXlab platform.

Passive Velocity Field control (PVFC). Part I. Geometry and robustness
IEEE Transactions on Automatic Control, 2001CoAuthors: P.y. Li, R. HorowitzAbstract:Passive Velocity Field control is a control methodology for fully actuated mechanical systems, in which the motion task is specified behaviorally in terms of a Velocity Field, and the closedloop system is passive with respect to a supply rate given by the environment power input. The control law is derived geometrically and the geometric and robustness properties of the closedloop system are analyzed. It is shown that the closedloop unforced trajectories are geodesics of a closedloop connection which is compatible with an inertia metric, and that the Velocity of the system converges exponentially to a scaled multiple of the desired Velocity Field. The robustness property of the system exhibits some strong directional preference. In particular, disturbances that push in the direction of the desired momentum do not adversely affect the performance. Moreover, robustness property also improves with more energy in the system.

Passive Velocity Field control (PVFC). Part II. Application to contour following
IEEE Transactions on Automatic Control, 2001CoAuthors: P.y. Li, R. HorowitzAbstract:When the contour following task is represented by a Velocity Field on the configuration manifold of the system, the coordination aspect of the problem is made explicit. The PVFC scheme developed in the Part I (ibid. vol.29(9) (2001)) can then be applied to track the defined Velocity Field. However, for some contours, an encoding Velocity held on the configuration manifold does not exist or is difficult to define and, as a consequence, the PVFC cannot be directly applied. For systems whose configuration manifolds are compact Lie groups and the desired contour is represented by a parameterized trajectory, a general methodology is developed, using a suspension technique, to define a Velocity Field on a manifold related to the configuration manifold of the system for which PVFC can be applied. With this strategy, timing along the contour can be naturally varied online by a selfpacing scheme so that the contour tracking performance can be improved. The experimental results for a 2DOF robot following a Lissajous contour illustrates and verifies the convergence and robustness properties of the PVFC methodology.

Adaptive passive Velocity Field control
Proceedings of the 1999 American Control Conference (Cat. No. 99CH36251), 1999CoAuthors: P.y. LiAbstract:Passive Velocity Field control (PVFC) was previously developed for mechanical systems which have strong coordination and must interact with the physical environment. Applications include teleoperated manipulators, contouring in machining and smart exercise machines. The methodology encodes tasks using time invariant desired Velocity Fields instead of the more traditional method of timed trajectories and guarantees that the closed loop system behave passively with environment power as the supply rate. By maintaining the passivity property of the closed loop system, stability and robustness will be enhanced, especially when interacting with uncertain environments. The present paper extends PVFC to situations where the inertia parameters of the mechanical system are unknown. A direct adaptive control scheme is proposed which preserves the passivity of the closed loop system and ensures that the asymptotic convergence of the Velocity to the direction of desired Velocity Field.

Passive Velocity Field control of mechanical manipulators
IEEE Transactions on Robotics and Automation, 1999CoAuthors: P.y. Li, R. HorowitzAbstract:Two concepts are advocated for the task specification and control of mechanical manipulators: 1) coding tasks in terms of Velocity Fields; 2) designing controllers so that the manipulator when under feedback control, interacts in an energetically passive manner with its physical environment. Based on these two concepts, a new passive Velocity Field controller is proposed which mimics the behavior of a passive energy storage element, such as a flywheel or a spring. It stores and releases energy while interacting with the manipulator, but does not generate any. The controller has the interesting property that it stabilizes any multiple (positive or negative) of the desired Velocity Field, and exponentially stabilizes the particular multiple of the desired Velocity Field which is determined by the total kinetic energy of the manipulator control system.

Passive Velocity Field control of mechanical manipulators
Proceedings of 1995 IEEE International Conference on Robotics and Automation, 1995CoAuthors: P.y. Li, R. HorowitzAbstract:Two concepts for the task specification and control for mechanical manipulators are advocated: the coding of tasks in terms of Velocity Fields; and controllers that maintain the passivity relationship between the manipulator and its physical environment. A passive Velocity Field tracking controller is proposed. The proposed dynamic controller mimics a flywheel: it stores and releases energy to the manipulator, but does not generate any. The controller has the interesting property that it stabilizes any multiple (positive or negative) of the desired Velocity Field, and exponentially stabilizes the particular multiple which is related to the total kinetic energy of the manipulator+controller.
M. Yamakita  One of the best experts on this subject based on the ideXlab platform.

Adaptive generation of desired Velocity Field for leaderfollower type cooperative mobile robots with decentralized PVFC
Proceedings 2001 ICRA. IEEE International Conference on Robotics and Automation (Cat. No.01CH37164), 2001CoAuthors: M. YamakitaAbstract:We propose an adaptive generation method of desired Velocity Field for leaderfollower type cooperative mobile robots with decentralized passive Velocity Field control (PVFC) which is a decentralized control algorithm of multiple robots handling a common object in coordination. The proposed control method for cooperative mobile robots is constructed by extending the PVFC. This research is different from the previous work in which a common desired Velocity Field for cooperative PVFC and all cooperative mobile robots was only following the same desired Velocity Field using the proposed method supervisor can easily specify the behavior of the mobile robots. The stability and boundedness of the resultant system with the proposed control algorithm is also guaranteed. Finally, the proposed control algorithm is examined by computer simulations for cooperative tasks with two mobile robots, and the results illustrate the validity of the proposed control algorithm.

Passive Velocity Field control of biped walking robot
Proceedings 2000 ICRA. Millennium Conference. IEEE International Conference on Robotics and Automation. Symposia Proceedings (Cat. No.00CH37065), 2000CoAuthors: M. Yamakita, F. Asano, K. FurutaAbstract:The study of bipedal walking in the framework of humanoid robot is a recent active research area. In this paper, we apply passive Velocity Field control to the control of a biped walking robot which walks on the level ground by actuators. Using this method, we can change the walking speed easily by modifying a virtual energy. The validity of the proposed method is demonstrated by numerical simulations.

Adaptive generation of desired Velocity Field for cooperative mobile robots with decentralized PVFC
Proceedings. 2000 IEEE RSJ International Conference on Intelligent Robots and Systems (IROS 2000) (Cat. No.00CH37113), 2000CoAuthors: M. YamakitaAbstract:We have proposed a decentralized control method based on passive Velocity Field control (PVFC) in previous works (1997, 1998). However, the feedback was localized and the desired Velocity Field was given by a central controller. The geometry cooperative multiple mobile robot system whose subsystem is under nonholonomic constraints and which conveys a common rigid object in a horizontal plain was proposed. In this paper, we propose a method to generate the desired Velocity Field for cooperative mobile robots with decentralized PVFC. The proposed control method for cooperative mobile robots is constructed by extending the PVFC and ensures the stability and boundedness using projection algorithm. Finally, the efficiency of the proposed method is examined by computer simulations for cooperative tasks with two manipulators.
J. Moreno  One of the best experts on this subject based on the ideXlab platform.

ICRA  Hierarchical Velocity Field control for robot manipulators
2003 IEEE International Conference on Robotics and Automation (Cat. No.03CH37422), 2003CoAuthors: J. Moreno, R. KellyAbstract:This paper concerns the Velocity Field control in operational space of robot manipulators. Velocity Field control is a recent control formulation in robotics. A Velocity Field defines the desired robot Velocity in the operational space as a function of its current position, thus the robot performs the desired motions. In this paper, a controller is proposed for operational space Velocity Field control. The proposed controller is based on a hierarchical structure that result of using the kinematic control concept and a joint Velocity controller. Experimental results on a two degreesoffreedom directdrive robot arm illustrate the viability of the proposed scheme.

Hierarchical Velocity Field control for robot manipulators
2003 IEEE International Conference on Robotics and Automation (Cat. No.03CH37422), 2003CoAuthors: J. Moreno, R. KellyAbstract:This paper concerns the Velocity Field control in operational space of robot manipulators. Velocity Field control is a recent control formulation in robotics. A Velocity Field defines the desired robot Velocity in the operational space as a function of its current position, thus the robot performs the desired motions. In this paper, a controller is proposed for operational space Velocity Field control. The proposed controller is based on a hierarchical structure that result of using the kinematic control concept and a joint Velocity controller. Experimental results on a two degreesoffreedom directdrive robot arm illustrate the viability of the proposed scheme.

Manipulator Velocity Field control with dynamic friction compensation
42nd IEEE International Conference on Decision and Control (IEEE Cat. No.03CH37475), 2003CoAuthors: J. Moreno, R. KellyAbstract:A Velocity Field controller for robot manipulators is proposed in this paper. The control structure is based on the use of a Velocity Field kinematic control scheme for joint Velocity resolution and a joint Velocity controller. Since dynamic friction is considered at the robot joints, the inner joint Velocity, controller uses an observer for friction compensation. The proposed scheme has been implemented on a two degreesoffreedom directdrive arm, illustrating the performance of the proposed observerbased controller.

A robust Velocity Field control
IEEE Transactions on Control Systems Technology, 2002CoAuthors: I. Cervantes, R. Kelly, J. Alvarezramirez, J. MorenoAbstract:This paper is devoted to Velocity Field control (VFC) of uncertain robotic manipulators. We propose a proportionalintegral (PI)type controller derived from modeling error compensation ideas and singular perturbation theory, that requires a minimum knowledge of the plant (i.e., constant estimate of the inertia matrix). It is shown that semiglobal practical stabilization is achieved; that is, given any compact set of initial Velocity Field errors, there exist PI control gains which guarantee that the robot tracks a desired Velocity Field with arbitrary accuracy. The proposed controller was experimentally evaluated on a two degreesoffreedom arm.
Javier Morenovalenzuela  One of the best experts on this subject based on the ideXlab platform.

CDC  On Passive Velocity Field Control of Robot Arms
Proceedings of the 45th IEEE Conference on Decision and Control, 2006CoAuthors: Javier MorenovalenzuelaAbstract:In the passive Velocity Field control the interaction between a robot arm and its physical environment is passive. If physical interaction is not presented the mechanical system moves along the integral curves of a desired Velocity Field with speed proportional to the initial stored energy of the robot. Motivated by Lyapunov's direct method, this paper extends the results in (Li and Horowitz, 1999) by presenting a class of controllers which solves the passive Velocity Field control objective. An important characteristic of the proposed approach is the shaping of the total kinetic and potential energy of the closedloop system dynamics. Besides, the problem of pure Velocity Field control is also considered, which consists in the following of the integral curves of a desired Velocity Field with speed proportional to a userdefined constant

A new Velocity Field controller for robot arms
Proceedings 2006 IEEE International Conference on Robotics and Automation 2006. ICRA 2006., 2006CoAuthors: Javier MorenovalenzuelaAbstract:By using only position measurements, in this paper is discussed a new control algorithm for Velocity Field control of robot arms. A Velocity Field defines the robot desired Velocity in the operational space as a function of its current position. The introduced algorithm is based on a hierarchical structure that result of using the kinematic control concept and a joint Velocity controller

On Passive Velocity Field Control of Robot Arms
Proceedings of the 45th IEEE Conference on Decision and Control, 2006CoAuthors: Javier MorenovalenzuelaAbstract:In the passive Velocity Field control the interaction between a robot arm and its physical environment is passive. If physical interaction is not presented the mechanical system moves along the integral curves of a desired Velocity Field with speed proportional to the initial stored energy of the robot. Motivated by Lyapunov's direct method, this paper extends the results in (Li and Horowitz, 1999) by presenting a class of controllers which solves the passive Velocity Field control objective. An important characteristic of the proposed approach is the shaping of the total kinetic and potential energy of the closedloop system dynamics. Besides, the problem of pure Velocity Field control is also considered, which consists in the following of the integral curves of a desired Velocity Field with speed proportional to a userdefined constant